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Public Citizen Health Research Group v. Tyson

Citation: 17 ELR 20056
No. Nos. 84-1252 et al., 796 F.2d 1479/(D.C. Cir., 07/25/1986)

The court holds that the long-term exposure limit issued by the Occupational Safety and Health Administration (OSHA) for ethylene oxide (EtO) is supported by substantial evidence, but that OSHA's decision not to issue a short-term exposure limit is not supported by the record. The court initially sets out the legal requirements, as interpreted by the Supreme Court in Industrial Union Department, AFL-CIO v. American Petroleum Institute, 10 ELR 20489, that OSHA must follow in setting exposure standards. The court then holds that OSHA's finding that exposure to EtO at the existing limit presented adverse health consequences is supported by substantial evidence. The court upholds OSHA's findings that EtO is carcinogenic, cytogenic, mutagenic, and hazardous to human reproduction. Although individual epidemiological and experimental studies may have been scientifically flawed, the court holds that the cumulative evidence supports OSHA's findings that a significant risk existed.

The court next upholds OSHA's use of a mathematical model to estimate the actual health risks posed by exposure to EtO. The court holds that OSHA's use of an animal study to supply the database for the model was supported by substantial evidence. OSHA, recognizing that animal studies do not translate perfectly into human terms, chose the best available data in this area of scientific uncertainty. The court also holds that two assumptions employed by the model are supported by substantial evidence. The court rejects the contention that the model unlawfully assumes that there is no threshold level of EtO exposure. Under the Supreme Court's decision, OSHA need not unequivocally prove the validity of every assumption it employs, but may employ assumptions that risk error on the side of overprotection if supported by a body of reputable scientific thought. The court holds that the model's nothreshold assumption is in fact supported by substantial evidence. The court also rejects the contention that the model improperly translates inhalation rates for rats into equivalent human responses. The court holds that even if OSHA overestimated the number of excess deaths caused by EtO exposure at the former standard, the error is insufficient to affect the validity of OSHA's final standard. In a note, the court holds that OSHA's requirement that employers post signs warning employees that EtO is hazardous is reasonably necessary and appropriate.

The court next holds that OSHA's decision not to issue a short-term exposure limit is not supported by substantial evidence. The court upholds OSHA's finding that exposure to a dose of EtO over a short time period produces greater effects than exposure to the same dose over a longer period. The court, however, holds that there is not substantial evidence to support OSHA's finding that a short-term limit is unnecessary because the long-term limit will simultaneously control short-term exposures. OSHA failed to account for exposure scenarios in which employers could allow high short-term exposures, but still have cumulative exposures below the long-term limit. The court orders OSHA to either adopt a short-term limit or explain why these exposure scenarios do not compel the issuance of a short-term limit. Finally, since the court remands OSHA's decision not to issue the short-term limit on statutory grounds, the court finds it unnecessary to reach the constitutional questions presented by the Office of Management and Budget's participation in this rulemaking.

[A related case is published at 13 ELR 20877.]

Counsel for Petitioners
David C. Vladeck, Alan B. Morrison
Public Citizen Litigation Group
2000 P St. NW, Washington DC 20036
(202) 785-3704

David H. Larry
Epstein, Becker, Borsody & Green
9th Floor, 1140 Nineteenth St. NW, Washington DC 20036
(202) 861-0900

Counsel for Respondents
Alfred R. Mollin
Civil Division
Department of Justice, Washington DC 20530
(202) 633-4331

Joseph M. Woodward, Laura V. Fargas
Department of Labor, 200 Constitution Ave. NW, Rm. S4004, Washington DC 20210
(202) 523-6623

Before ROBINSON, Chief Judge, WRIGHT*, Circuit Judge, and McGOWAN, Senior Circuit Judge.